<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <div id="app">
        <h2>加加减减</h2>
        <ul>
            <li v-for="(item,index) in list" :key="item.id">
                {{ item.num }}
                <button @click="del(item.id)">删除</button>
            </li>
        </ul>
        <button @click="add()">生成</button>
    </div>

    <script src="../js/vue.js"></script>
    <script>
        const app = new Vue({
            el: '#app',
            data: {
                list: [
                    { id: 1, num: Math.floor(Math.random() * 20) },
                    { id: 2, num: Math.floor(Math.random() * 20) },
                    { id: 3, num: Math.floor(Math.random() * 20) }
                ]
            },
            methods: {
                add() {
                    this.list.push({
                        id: this.list[this.list.length - 1].id + 1,
                        num: Math.floor(Math.random() * 20)
                    })
                },
                del(id) {
                    this.list = this.list.filter(item => item.id !== id)
                }
            }
        })
    </script>
</body>

</html>